Real Fiero Tech

Did you check your throw out bearing? I know those are normally only noisy when you disengauge the clutch so I doubt that is the problem but just a thought.

Yeah its brand new. No play in it or anything. IIRC the noise doesnt go away right when the throwout bearing touches the pressure plate; it goes away after the clutch is actually disengaged. I need to do some further testing when I'm back at my car next weekend. Just trying to get some ideas of what to look for.

I had a bad spring in my old clutch. It was starting to work itself loose, but I never had a rattle in my tranny from it.

YOu able to tell if the rattle is from the input shaft area or actually inside the tranny case itself?

No; that's a good point.. I should get a stethoscope and see where its really coming from.

you got fluid in the tranny right?

Yeah synchromesh up to the full mark.

I did some extensive diagnosis tonight. My friend Chris came over with a stethoscope and we played doctor for an hour or so. The noise is coming from the input shaft; either the front bearing or the rear bearing. Most likely the front bearing.
The noise is much louder than any other mechanical noise from the drivetrain with the engine running. It's a whirring/clunking/tapping sound. It is higher pitched and louder from the front of the case, even though there isn't a place on the exterior of the bellhousing that is directly over the input shaft bearing. It is still loud, but sounds more dull at the back of the case, right on the rear input shaft case bearing.. so its probably not that bearing.
The noise goes away when the clutch is fully disengaged with the engine running (i.e. the input shaft has stopped spinning). Partial disengagement doesn't have any effect on the noise, so that rules out the throwout bearing.
When the engine is turned off, but with the transmission in gear and the clutch disengaged, we pushed the car around and listened. The noise is present but goes away in higher gears, likely because the ratios keep the movement of the input shaft to a minimum at the speed we were able to push the car. It's loudest in first and second.
The input shaft bearing is new. However, the input shaft felt like it still had a tiny bit of play in it after I replaced the bearing. I wiggled it up and down and heard a ticking noise.
Sooo apparently the input shaft is worn (the shaft itself is the inner race) or the bearing is crap/defective. I guess I'll just have to live with it until it blows up.

a whirring clacking noise is usually a flatted ball bearing - chances are high its a bad TO bearing

edit: by disengaged i was thinking backwards - thinking of the TB being disengaged rather than pushing fully in to disengage the clutch.

i've had to bearings chirp when released but never that sort of noise.

the only things different when he clutch in engaged vs disengaged are..

to bearing position and pressure
clutch pressure plate finger position
clutch pressure plate and flywheel rotation vs friction disk rotation
pressure on the face of the crank

for it to make a noise only when the to bearing is released and the clutch is engaged the only things not moving together are the to bearing and the clutch fingers
it also started the tranny internals into motion. missalignment between engine and tranny could cause problems, especially if there was slop int he input shaft causing an initial misalignment. it may never be able to align once the clutch grabs. and will quickly destroy the bearing.

Kohburn wrote:a whirring clacking noise is usually a flatted ball bearing

Rear input shaft case bearing is all it could be if thats the case. The only ball bearings in the tranny are the rear case bearings. All other bearings in the tranny are rollers or needles.. I wonder if I could devise a way to replace those without splitting the case. If I could pull the bearing out as I pushed in the shaft, i could do it. The bearing isn't very tightly pressed into the case, and it's readily accessible with the rear cover off. Hmm..
If I can grab the bearing with a puller with the center part of the puller on the shaft, I should be able to pull the bearing out of the case without the shaft going anywhere. Then I would only need to knock the bearing on to where I can get the bolt to engage, and use it to pull the input shaft the rest of the way into the bearing.

for it to make a noise only when the to bearing is released and the clutch is engaged the only things not moving together are the to bearing and the clutch fingers

Since it seems to happen with the engine off its not the throwout bearing. Also I would think that noise would change as the load on the bearing increases (i.e. pressing in the clutch).
The throwout bearing felt and sounded fine when I spun it by hand when it was out of the car last. It's brand new, BTW.

it also started the tranny internals into motion. missalignment between engine and tranny could cause problems, especially if there was slop int he input shaft causing an initial misalignment. it may never be able to align once the clutch grabs. and will quickly destroy the bearing.

Yeah I was thinking the same thing. I think if the input shaft is worn, the input shaft will sit at the bottom of the bearing while not in motion, then when the clutch engages it'll grab off center and stay that way, hence the awful clacking noise as it spins around off center. I experimented earlier with slowwwwllyyyy engaging the clutch to see if it made the sound quieter. I couldn't tell for sure but it seemed to have an affect. Sometimes if I would push in the clutch and let go it would be a lot louder than it was before.

Is your input shaft straight?

Its been a couple years, but I think that ball bearing has a snap ring on the inside of the case, which means its put in the case first, and the snap ring holds it from coming out the bottom. Then the gearset/shaft is installed into the bearing. I really cant be sure so just get an exploded view of the case before trying to pull it out the end.

The Dark Side of Will wrote:Is your input shaft straight?

I don't know. I've put over a thousand miles on the transmission though and nothing has broken. Have the Getrag input shafts been known to get bent somehow? I never dropped it or anything.. Seems like it would've had trouble getting the case together if it were bent.

p8ntman442 wrote:Its been a couple years, but I think that ball bearing has a snap ring on the inside of the case, which means its put in the case first, and the snap ring holds it from coming out the bottom. Then the gearset/shaft is installed into the bearing. I really cant be sure so just get an exploded view of the case before trying to pull it out the end.

Nah, that snap ring is on the outside of the case.

Series8217 wrote:Yeah synchromesh up to the full mark.

...I did some extensive diagnosis tonight. My friend Chris came over with a stethoscope and we played doctor for an hour or so...

LOLOLOL!!!!!!!11!!1111one111eleven1211 :la:

I have a 282 from an early 90's cavalier with the revised oiling input and output shafts but my desired 1st, 2nd, and final drive. I'm going to take it apart tonight and inspect it thoroughly, then over spring break I'll rebuild the trans with those parts as well as new case bearings at the front and rear. Hopefully that will solve the rattle and gear whine that I hear.
Anyone have a source for the front input shaft bearing/seal/sleeve?

just call a local transmission rebuild shop, they will be able to order the transmission rebuild kit with the roller needle bearings, shaft end bearings, and everything else. The kit should run around $125. This obviously does not include new synchros, or blocker rings.

I already have new shaft end bearings. I already have all the new needle rollers that are still available (from GM at least). All I need is the input shaft front bearing.
What needle rollers are available in the aftermarket that GM doesn't have? I think I have 3rd and 5th but I can't remember for sure.. I just used those new ones and then for the rest the newest out of the two transmissions I was taking parts from.
For what its worth, the rebuild kit I got came with everything except the needle bearings for the gears and the needle bearing for the shift shaft. It literally had everything else including the shift shaft seal, new detent housing cover, diff bearings, axle seals, blocker rings, etc. I didn't see any that came with needle bearings..

3rd and fifth are the only two with needle bearings arnt they? 1-2 is a set pressed on, and stationary, and so is 4th? Again, its been a couple years since I rebuilt a getrag.

They all do. If they're stationary on one shaft they have to idle on the other shaft until they're engaged...

Those needle bearings live VERY easy lives, however.
When they're spinning, they're not loaded.
When they're loaded, they're not spinning.

Replacement of them is seldom truly necessary.

Series8217 wrote:They all do. If they're stationary on one shaft they have to idle on the other shaft until they're engaged...

DUH, That makes sense. I only rebuilt my input shaft as the fifth gear bearing had been wiped out and run long enough to ruin the shaft.

Will, would you mind breaking my input shaft troubles stuff into a seperate thread (move to maintenance?). I didn't really mean to get this one so off topic from the flywheel stuff...